IndentingWriter


1   package org.apache.beehive.controls.runtime.generator;
2   /*
3    * Copyright 2004 The Apache Software Foundation.
4    *
5    * Licensed under the Apache License, Version 2.0 (the "License");
6    * you may not use this file except in compliance with the License.
7    * You may obtain a copy of the License at
8    * 
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   *
17   * $Header:$
18   */
19  
20  import java.io.IOException  ;
21  import java.io.Writer  ;
22  
23  /**
24   * The IndentingWriter class is a simple implementation of an indenting code writer
25   */
26  public class IndentingWriter extends Writer   
27  {
28      /** current depth:
29       * <PRE>
30       * // depth = 0;
31       * {
32       *   // depth now is 2
33       *   {
34       *     // depth now is 4
35       *   }
36       *   // depth now is 2
37       * }
38       * // depth now is 0
39       * </PRE>
40       */
41      protected int depth = 0;
42  
43      public IndentingWriter(Writer   delegate) 
44      {
45          this(delegate, 
46               Integer.getInteger("org.apache.beehive.controls.runtime.generator.indentLevel", 4).intValue());
47      }
48  
49      public IndentingWriter(Writer   delegate, int indentLevel) 
50      {
51          _out = delegate;
52          this._indentLevel = indentLevel;
53      }
54  
55      public void write(char cbuf[], int off, int len) throws IOException   
56      {
57          if (off < 0 || off + len > cbuf.length)
58              throw new ArrayIndexOutOfBoundsException  ();
59  
60          for (int i = off; i < off + len; i++) 
61          {
62              char c = cbuf[i];
63              if (c == '}') 
64              {
65                  decrDepth();
66              } 
67              else if ((c == ' ' || c == '\t') && _needIndent) 
68              {
69                  continue;
70              }
71  
72              if (_needIndent)
73                  indent();
74              _out.write(c);
75  
76              if (c == '\n')
77              {
78                  _needIndent = true;
79              }
80              else if (c == '{') 
81              {
82                  incrDepth();
83              }
84          }
85      }
86  
87      public void flush() throws IOException   
88      {
89          _out.flush();
90      }
91  
92      public void close() throws IOException   
93      {
94          _out.close();
95      }
96  
97      private void indent() throws IOException   
98      {
99          for (int i = 0; i < depth; i++) 
100         {
101             _out.write(' ');
102         }
103         _needIndent = false;
104     }
105 
106     private void incrDepth() 
107     {
108         depth += _indentLevel;
109     }
110 
111     private void decrDepth() 
112     {
113         depth -= _indentLevel;
114         if (depth < 0)
115             depth = 0;
116     }
117 
118     protected Writer   _out;
119     protected int _indentLevel;
120     private boolean _needIndent = false;
121 }
122
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